Morphological and histochemical changes occurring in mammalian lenses during development of hereditary and senile cataracts are to be studied. The histochemical experiments are aimed at further exploration of transport and digestive properties of the lens, including Na/K-ATP-ase and acid phosphatase location, and protein uptake. Laboratory animals involved in these investigations will be rats. Slit lamp examinations will precede utilization of lenses for light microscopy and electron microscopy. It is anticipated that this research will yield further information concerning cataractogenesis in useful experimental animal models.